Explosive composition



y 1949- w. F. VAN LQENEN 2,477,549

EXPLOS IVE COMPOSITION Filed Jan. 22, 194"! WIl/Iam Mm LOBHQ" IV E/VTORBy l/ flGENT Patented July 26, 1949 EXPLOSIVE CQMROSITION William F. VanLoenen, Los Altos, Califi, assignor to The Permanente MetalsCorporation, Oakland, Calif., a corporation of Delaware ApplicationJanuary 22, 1947, Serial No. 723,519

13 Claims.

This invention relates to an explosive composition and more particularlyto an explosive composition containing magnesium dust, or very finelydivided magnesium metal.

The explosive composition of this invention comprises an oxidizing agentand finely divided magnesium, or magnesium dispersoid, obtained byshock-chilling magnesium vapor or gas mixtures containing the same. Theshocl -chilling is effected with fluid agents, such as hydrogen, naturalgas, hydro-carbons, etc., which are substantiall inert toward themagnesium under the conditions of operation. A preferred method ofobtaining the magnesium dust, or dispersoid, useful in this invention isto recover the crude condensate obtained in the carbothermic process formaking magnesium metal. In addition to the magnesium dust, modified tosuitably decrease its reactivity, the composition preferably includes asolid oxidizing agent in sufficient amount to satisfy all of thecombustible material in the composition.

The magnesium dispersoid useful in this invention and obtained asdescribed'is of a fineness beyond any obtainable by mechanicalcomminution of massive metal. The particle size of the magnesiumobtained by shock-chilling the metal vapor approximates colloidal sizes.Such small particles cannot be obtained commercially in any case bygrinding, and there are special disadvantages encountered in grindingmagnesium which becomes so highly reactive upon sub-division, forinstance that grinding must be eiiected under an inert atmosphere. Thus,it is not known that magnesium can be mechanically comminuted to theultimate particle sizes characteristic of the magnesium dust useful inthis invention, as more fully described below. This magnesium is sofinely divided that, more than being merely pyrophoric, it reacts withexplosive violence when exposed to sources of oxygen.

It has now been found that the magnesium dispersoid is not onl explosivein gas dispersion but also when dispersed in a liquid, with sufiicientoxidizing agent, and when it is present in a solid mixture, withsufiicient oxidizing agent, although the means of initiating theexplosion may vary with these three states, as Well as with theexplosive reaction desired.

As stated above, a preferred method of obtaining the magnesiumdispersoid is by recovery of the crude magnesium metal condensateobtained in the carbothermicprocess for making magnesium metal, in whichprocess magnesium oxide is reduced by a carbonaceous reducing agent asdisclosed in U. S. Patent 1,884,993, to Hansgirg, and in U. S. Patent2,328,202, to Doerner, and other patents and journals. Therein a mixtureof magnesium oxide and carbon is converted into ma nesium vapor andcarbon monoxide by the heat of an electric arc furnace. This gaseousmixture is discharged from the region of the arc at a high enoughtemperature (above 1800 C.) that reversal of the reaction does not occurto an appreciable extent, and is then suddenly cooled and diluted byinjecting large volumes of a shockchillin agent, which may be hydrogen,helium, natural gas, hydrocarbon Vapor or even a spray of liquidhydrocarbon.

In one particular practice of the process natural gas is'employed. Themagnesium vapor is condensed tomagnesium metal in the form of extremelyfine dust which is essentially a smoke. Some of the vapor recombineswith carbon monoxide with the result that the solid materialprecipitated in the condensing chamber comprises a substantialproportion, from 30% to of magnesium dust with the remaining to 35%comprising carbon,magnesium oxide and impurities.

This condensate, that is, the magnesium dust with admixed impurities, ismodified in various ways to reduce its activity in air in order that itmay be processed to an explosive composition. By activity is meant thetendency of the material to react chemically.

A particularly advantageous method of modifying the magnesium dispersoidis to treat it with liquid hydrocarbon or a liquid mixture ofhydrocarbons to provide the magnesium particles with a protectivecoating. This method is simple, effective and economical, and, in fact,is inherent in the process Where the magnesium vapors are shock-chilledwith a liquid hydrocarbon spray or a hydrocarbon gas which condensesunder the conditions of operation.

The dust wetted with hydrocarbon is for convenience called carbothermicmagnesium paste. The magnesium dust, or crude condensate, recovered fromthe shock-chilling step is usually treated with a liquid hydrocarbonsuch as kerosene or oil, having a flash point above 1 K, and with orwithout added asphalt or pitch, to produce a relatively stiff plasticmass.

The average analysis of the magnesium. dust from the carbothermicprocess is, for example:

Inert (principally MgO 4--.. 31

A small percentage of the magnesium (approximately 5%) exists as one orboth of the carbides, MgCz and MgzCs. It is believed that the presenceof these carbides is advantageous in that they may yield acetylene incombination with the water formed by the oxidation of the hydrocarbon,the acetylene being explosive under mildly increased pressures. There isgenerally a trace of sodium which is believed to be in elemental formand possibly minor traces of other carbides such as those of calcium,silicon and/or aluminum originating from the ash constituents from themetallurgical coke in the reduction furnace, or the minor ashconstituent of the petroleum coke reducing agent, or impuritiesassociated with the starting oxide. With the exception of occasionalcarry over of particles from the reduction zone, all of these materialshave an ultimate particle size below the resolving power of opticalmicroscopes. Electron microphotographs reveal agglomerates severalmicrons in diameter but ultimate particles are in the neighborhood of0.1 micron diameter.

The hydrocarbons which may be employed for wetting the crude magnesiumdust may advantageously comprise a mixture of coke still distillate orkerosene and of asphalt which is a welldistilled residue of an uncrackedasphaltbase oil. Although the proportions may vary as stated below, itis usually preferable to employ mixtures containing about 5% to asphaltand about 95% to distillate or kerosene. A 90/10 mix contains 90%distillate and 10% asphalt, a 55/45 mix contains 55% distillate and 45%asphalt, and so forth. Thepercentages given are by weight. Typicalanalyses of the components of the mixture are as follows:

Distillate Gravity, API at F 10.2

Flash point Pensky-Martin closed cup F 180 Viscosity Saybolt secondsUniversal at 100 Asphalt Gravity, API at 60 F 1112 Flash pointPensky-lvlartin closed c up' F" 430 Viscosity Saybolt seconds Furol at210 PL... 145

The hydrocarbon mixture may contain any desired proportion of asphalt,such as the abovedescribed asphalt, pitch or like substance.

In the production of a mixture of magnesium dust and hydrocarbons, safefor shipment and suitable for compounding explosive mixtures theshock-chilled dust is conveyed in a closed atmosphere under hydrogen ornatural gas, or other inert gas, to a suitable mixing machine where itis thoroughly mixed with the desired hydrocarbons and can then be loadedinto open drums. Practical concentrations are usually made of between55% and 70% solids, the balance hydrocarbons. For reasons of safety itis undesirable to include low flash hydrocarbons at this stage. Variousmixtures of fuel oils, or kerosenes in a considerable range, arepractical from a production standpoint. This magnesium material whenthorough- V ly wetted with hydrocarbons is not easily ignited nor willit flash or explode upon handling.

Magnesium or powdered magnesium has heretofore been known to the art asa constituent of explosive compositions. These compositions have beenmade by first producing magnesium in solid metal form and thensubdividing it. By the method of the present invention the raw powdercoming from the shock-chilling step of the carbothermic process isdirectly used in the composition. The metal in its dry dust ordispersoid form is of a state of subdivision far greater than that whichit is possible to produce by mechanical subdivision. The finely dividedmagnesium produced in the carbothermic process has a particle size ofsubstantially less than one micron, and as heretoiore stated is capableof spontaneous combustion with the atmosphere unless coated with amaterial such as a liquid hydrocarbon or otherwise modified. It isobvious that a particle size of this order cannot be achieved inquantity on a commercial scale by the use of mechanical means. Thusparticular characteristics of this invention are that it utilizes finelydivided magnesium and carbon of a particle size never before utilized inexplosive compositions, and yet such finely clivided magnesium andcarbon are capable of rapid and economic production, and the mixture canbe safely handled.

In employing the carbothermic magnesium dust, as described above, in theexplosive composition of this invention, there are provided in thecomposition particles of magnesium which approximate colloidal size aswell as particles of carbon of similar or even smaller size. When thevapors .from the reduction zone, comprising lvlg and C0, areshock-chilled to produce the crude condensate someback-reaction occursinevitably, although shock-chilling holds it to a minimum. The reversalis as follows? This reaction serves to produce materials of ex-. tremelysmall particle size. It is believed that the fineness and purity of thecarbon obtainedare advantageous in this invention. It is also believedthat the highly adsorbent characteristic of the carbon of thecarbothermic dust is advantageous in the composition of this invention.Figure 1' is an electronmicrograph, taken at 32,000 diametersmagnification, of crude magnesium dust recovered as condensate in thecarbothermic process as described above. It will be observed that thegreater proportion of the dustappears as submicronic spheres and themetal particles are held in agglomerates which also contain carbon, MgOand other impurities. Many extremely fine particles are scattered overthe field. The subdivision of the constituents speeds up the combustionof the magnesium, and other fuel which may be present, to causedetonation.

In an explosive composition, according'to this invention, whichcomprises carbot-hermic dust uniformly dispersed within and modified bya protective coating of hydrocarbon, and a solid oxidizing agent, it isbelieved that when the explosive reaction is initiated the protectivecoating is either burned off or the'lighter' constituents thereofvolatilized, exposing some of the magnesium surface, which then oxidizeswith extreme rapidity, in the presence of suflicient oxidizing agents.This produces sufficient heat of combustion to'va'porize the balance ofthe hydrocarbon,

as to the present invention that, after initiation of the reaction, theburning of the first 'magnesium particles effects vaporization ofcumcreasing with the temperature, and, therefore,

in carbothermic magnesium dust recovered by shock-chilling of themagnesium-containing vapors with hydrogen or with hydrocarbons whichcrack to yield hydrogen, the metal dispersoid particles contain hydrogenin solution or in occlusion, which will also be available in theexplosive reaction and will thus enhance the reactivity of thismaterial.

The oxidizing agents useful in the composition of this invention aresolid oxiding agents, for example, nitrates of sodium, potassium,ammonium, guanidine, strontium, barium, lead etc.; metal chlorates, suchas sodium or potassium chlorate; metal perchlorates, such as sodium orpotassium perchlorate; or mixtures of such oxidizing agents. In general,mixtures of two or more oxidizing agents result in slightly moresensitive compositions. In addition to these oxidizing agents, thepresence of small amounts of water, preferably not greater than 1%, issometimes advantageous. It is not necessary that the oxidizing agentcomponent be employed in the anhydrous state, so long as the watercontent does not exceed about 1% of the total explosive mix, and it istherefore helpful in some cases to add a small amount of water to thefinished mixture, or to employ a deliquescent oxidizing agent, such as,for example, ammonium nitrate. A preferred oxidizing agent, in manyuses, is a mixture of sodium nitrate with a minor proportion ofpotassium nitrate. The use of potassium nitrate enables preparation of acomposition which behaves well upon pressing, as in mudcappingoperations.

It is among the objects of the invention to produce an explosivepartaking of some of the characteristics of a black powder, in that forexample it can be defiagrated under some conditions, and also partakingof some of the characteristics of a detonating explosive, in that it canbe detonated upon proper initiation, as by a blasting cap. The explosivecomposition of this invention exhibits advantages over both types ofexplosives mentioned. One of the advantages of the present explosive isthat the ingredients can be mixed and the composition prepared withoutthe development of headaches by the workers, which often occur inworking up the nitrated organics. Also, the present composition can becontrolled to act either as a defiagrating or as a detonating explosiveby suitably choosing the means to initiate its reaction. The presentcomposition can be compounded in as little as 5 minutes mixing, in thesame type of apparatus as that in which 3 hours mixing time is requiredfor compounding black powder. The composi" tion of this invention iseffective as an explosive at lower bulk densities, which is advantageousin .blasting operations wherein the charge is placed by pneumatic means.Other objects and advantages will be apparent from the furtherdescription below. A a v Depending upon the use for which it 'is inii i)tended, the explosive composition is set on by a spitter fuse, by ablasting leap, by a combination of both of these means, or by using ablasting cap and a detonating fuse. For instance, to use the compositionas a blasting powder where a greater shattering is desired, it is mostsuitable to initiate reaction with a blasting cap and a safety fuse, ora booster charge such as tetryl or trinitrotoluene. A suitable safetyfuse is the Well known Cordeau or Cordeau-Bickford, which istrinitrotoluene encased in a tube of lead.

In preparing the explosive composition of this invention, the magnesiumdispersoid, modified to reduce its activity to where it will no longerspontaneously burn upon exposure to air, is admixed with solid oxidizingagent. I'he two compounds are suitably first comminuted separately tothe desired degree if necessary, for instance, by grinding the oxidizingagent and separately crushing the magnesium dispersoid-hydrocarbonmixture when the latter mixture is dry and solid enough to crush; andthen the comrninuted components are mixed together. Such mixing issometimes effected by tumbling the components together, and sometimes itis carried out in a Ciearfield mixer or other mixer of the muller type.Any desired mixing means can be employed. When the magnesiumdispersoid-hydrocarbon mixture is quite pasty, the paste is suitablymixed into the dry oxidizing agent which usually sorbs suificient of theliquid constituents to convert the mixture to a fine-grained powder.Alternatively, the oxidizing agent can be mixed into the paste. Toreduce grinding time, in preparation of the oxidizing agent, a grindingaid can be added if desired. A suitable grinding aid has been found tobe the residue obtained after distilling or subliming magnesium metalout of the crude carbothermic magnesium condensate or dust, this residueconsisting principally of finely divided MgO and carbon and smallamounts of impurities carried over from the carbothermic reducing zoneor those formed in the shock-chilling step, such a magnesium carbide.

It has been found that an explosive effect is obtained with as little asabout 15% by weight of oxidizing agent, based on the total weight of thecomposition, when the reaction is initiated in a suitably confinedspace. In many cases it is preferred to have at least by weight ofoxidizing agent present. In making a granular, or solid, explosive it ispreferred that the composition contain from about to about 85% by Weightof oxidizing agent per from about 1 35% to about 15% by weight ofmagnesium dispersoid modified to reduce its activity in air. Excellentresults as to strength and brisance are obtained when the compositionincludes about by Weight of oxidizing agent and about 25% by weight ofthe modified magnesium dispersoid. With the smaller pro-portions ofoxidizing agent it has been observed that the explosive compositions ofthe invention are eifective as propellants for projectiles or rockets.

The following examples will serve to illustrate this invention, but arenot intended to be limiting.

Example I 200 lbs. of fertilizer grade sodium nitrate and 5 lbs. of agrinding aid which is the residue remaining after sublimation ofmagnesium metal from crude carbothermic dust and which com- 40 inchscreen. It is advantageous to screen the mixture to remove any trampmetal therefrom. The screened mixture is placed in a Clearfield mixerand there are added 66 lbs. of 55/45 carbothermic magnesium paste. Themixer in this example includes a rotating bowl over which are suspendedone or more heavy wheels which revolve on an axle which is free to moveonly in a vertical plane, and the wheels are conveniently maintainedabout inch above the grinding or mixing surface of the bowl. In thismixer means are also provided to break up any caked material andredirect material beneath the muller. Any other desired mixer can beused; The one here described gives a mulling action to themixture andincludes both a pressing and a rubbing action. When the components ofthe mixture have been placed in the mixer, the mixing action is begunand is completed in about minutes. The result is a powder, and it istransferred to suitable containers for transport to storage or to theplace of use.

The composition as described in Example 1 is used in a number of ways.For instance it is used in quarrying operations for providing quarts foruse in ferrosilicon production. In one such operation, several verticalholes of three-inch diameter are drilled to a depth of 18 to 20 feet inthe quartz deposit. The holes are'sprung with about 3 lbs; of a quitebrisant explosiveas described below in Example 3. After blowing out theholes to remove shattered particles, about one-half the total charge foreach hole, of the composition of Example 1 is poured into theholes.

.A primer or ignition device which is a small bag of say, /4 lbs. of thecomposition of Example 1 surrounding an electric blasting cap andprovided with suitable insulated lead wires, is then lowered on top ofthe first portion of the powder charge, and then the balance of thepowder in, leaving stemming space, and the hole stemmed with loose sand.An electric blasting cap is attached to the Cordeau and the explosioninitiated thereby, to obtain a greater shattering effect.

"To obtain maximum explosive eifect, the explosive composition ofExample 1 is placed by pneumatic means. For instance, 3" holes aredrilled, both horizontally and at an angle to the horizontal, in thequarry face, and a detonating fuse is placed the full length of eachhole. The

. powder explosive charge is then placed by means of an aspirator usingcompressed air, and the air flow is of such slow velocity as to permitthe solids carried thereby to settle by gravity into .the hole. By thismethod of placement, the charge is deposit-ed in loose, fluffy conditionand maximum explosive effect is thereby obtained.

When the hole is charged to the desired depth,

7 a clay plug is pushed into thehoie withdistortion to causeit to swelland grip the sides of the hole, taking care notto' compact very greatlythe .outer end of thecharge; Then the rest of the .hole

.above the plug is packed tightly with clay or other stemming materialbefore explosion is initiated.

stead of spitter fuse.

Another method of blasting with the composition of Example I is topackage it in paper cartridges about 2 inches in diameter and 12 incheslong, which are tamped into the drilled holes without compacting thepowder to any appreciable extent. The explosion is convenientlyinitiated by a detonating fuse as before. In the foregoing tests,electric blasting caps have been used to initiate the explosion as, inusing a free flowing powder as charge, the hazards of handling areminimized. However, the use of spitter fuse and cap to ignite the chargeis also successful, care being taken to see that no loose powder ispermitted to remain near the fuse.

The foregoing tests have describeda blasting powder of the detonatingtype, useful especially where a shattering effect is desired. Theexplosive composition according to this invention is also useful as adeflagrating explosive, in operations where shattering from too greatbrisance is not desired, an example of which follows.

Example 2 lbs. of sodium nitrate and 20 lbs. of potassium nitrate areground together in 'a ball mill. The ground mixture is placed in a mixerof the type described above and mixed. for 10 minutes with 33 lbs. of66/40 carbothermic magnesium paste, the paste containing about 70%solids, and the starting magnesium dust condensate about "i% magnesiummetal dispersoid.

The composition of Example 2 is used, in one test, to split an oak log20 inches in diameter and 6 feet long; A hole inch in diameter and 10inches deep, is bored, on a diameter, about 12 inches from the end ofthe log. About 40 grams of the composition of Example 2 are pouredloosely into the hole and a spitter fuse is inserted into the charge.The hole is then filled up with loose sand and closed with a wooden plugpro vided with a hole just large enough to allow the fuse to passthrough in close-fitting relationship, the plug filling the top of thehole without effecting appreciable compacting of the charge. The spitterfuse is ignited, and the resulting ex plosion splits the log on itsdiameter and for its whole length.

When the explosion is initiated in a confined space by means of aspitter fuse, the detonation is muchless brisant than if the same chargeis set off by means of an explosive detonatore For example, in anothertest with a log 20 inches in diameter and 6 feet long, a hole is boredas described above, and charged in the same way exceptthat a No. 6electric blasting cap is used in- The explosion initiated by theblasting cap shatters thelog intoseveral segments, withbrealcing acrossthe grain.

Another use of the powder compos'itionof Example 2 is in limestonequarrying operations. For instance, a 2 inch vertical hole is drilled toa depth of ft., approximately parallel to and aboutSO feet. back of theface of a limestone quarryfrom which it is desired to obtain limestonefor manufacturing cement, for which pur pose the stone should be wellbroken up by the blasting action. A detonator is prepared byattachingsmall pellets of tetryl which is a brisant booster explosive, to a loopof cordeau, the pellets being about 12 inches apart. The loop'soprepared is lowered into the hole and the charge or the composition ofExample ;2 is poured into the about 3000 lbs) hole to fill about 75 feetof its depth (requiring The balance of the hole is 9 stemmed, or filled,with loose sand, and explosion initiated by cap and fuse. The quarryface is shattered by the explosion with excellent recovery ofsmall-sized limestone particles.

Example 3 In another test of the composition accordin to the presentinvention, it is used in an operation known as mudcapping. For thisoperation a brisant explosive is required and is made as beforedescribed except that the components comprise 75% by Weight of potassiumnitrate and 25% by weight of carbothermic magnesium paste. The finalmixture is a free flowing powder. In the explosive of this example,somewhat greater density of loading is suitable in using the explosive,that is, the powder can be Slightly compressed. Thus, the powder isparticularly useful in surface blasting or mudcapping. Potassiumperchlorate is also useful in the composition when intended for theseoperations.

In an example of. this use, 15 lbs. of the explosive composition ofExample 3 are placed on top of a boulder consisting of about 650 cu. ft.of dolomite. The powder is placed in a conical pile over a depression inthe rock surface, and a 15-- gram tetryl pellet is placed thereon, witha No. 6 blasting cap placed in contact with the pellet. Paper is laidover the charge, and then a layer of mud is added and patted downfirmly. The compression thereby effected does not reduce the force ofthe explosion and, upon initiation, the rock is shattered. A suitableamount of cordeau can be substituted for the tetryl booster.

ExampZe 4 A composition is prepared by admixing '70 lbs. of sodiumnitrate passing a screen having 40 meshes to the inch with 34 lbs. of55/45 carbothermic magnesium paste, and then adding 35 lbs. of potassiumperchlorate. Four lbs. of this composition are effective in blasting outan oak stump five feet in height and ten inches in diameter, withcomplete removal of the stump.

In making a defiagrating explosive, such as is used in firecrackers,potassium perchlorate is mixed with 90/10 carbothermic magnesium pastewhich has been dried to granules. Suitably the granules are ground topass a ZO-mesh, or smaller, screen and then mixed with the oxidizingagent.

Example 5 A composition is prepared as follows: 45 lbs. of sodiumnitrate are ground a ball mill until the product passes'through aLO-mesh screen. In a separate operation on a dough-mixer, '75 lbs. of55/45 carbothermic magnesium paste are mixed with sufiicient oil, asdetermined by observation, of the same. composition as was used inmaking the paste, that is, 55% kerosene and 5% asphalt residium, toproduce a sticky plastic mass. The ground sodium nitrate is added to thesticky mass in the dough mixer and mixing is continued for approximatelyminutes, or until a uniform dispersion is obtained. To this is addedmore of the 55/45 oil to bring the total amount of oil added to a totalof 25 lbs. This added oil reduces the consistency of the mixture to athick slurry which is useful as a propellant explosive for rocketprojection. The mixture is a defiagrating composition which when firedin a shell with a suitable orifice burns with sufficient rapidity thatthe ejected products cause rapid movement of the projectile.

In a test of this material, 160 lbs. of a composition made as above isloaded intoan aerial bomb shell weighing 250 lbs. before filling andprovided with an orifice at the rear which has an inside diameter of 2inches. In this test, the closure of the orifice is effected by sealingwithin it a glass bottle of suitable diameter, containing the initiatingcharge and having a plastic screw cap. The wires of the detonator arethreaded through an aperture in the cap and sealed therein with asealing compound. The initiating charge in the glass bottle (or otherfrangible container) comprises about 60 grams of black powder, or otherslow deflagrating composition, and an instantaneous electric detonator.Within the nose of the bomb shell is disposed a second powder well madeof thin metal in which are placed about 40 grams of black powder and aninstantaneous blasting cap. When the reaction is initiated with asuitable electric contactor, the explosion resulting does not burst thebomb casing but instead the products of explosion are discharged throughthe rear orifice, opened by the breaking of'the glass, or other,container, propelling the projectile for approximately one mile.

Alternatively to the examples shown above, when using the composition asa deflagrating explosive, reaction is conveniently initiated by means ofa squib. In operations where greater brisance is required, some of whichhave been described in the above examples, initiation of the reactionwith the aid of brisant booster explosive is advantageous. Such abooster can be tetryl, cordeau, primacord, nitroglycerin dynamite orother booster explosive. Brisance can also be increased by increasingthe resistance, or pressure. against which the composition explodes,without effecting compression of the explosive composition itself; thatis, the heat of combustion and products of combustion are confined for ashort period at the time of explosion. In other words, the explosiveaction is intensified or enhanced, or sometimes even effected, when themeans which are employed to contain the explosive are of higher breakingstrength, such as a suitably sealed shell casing, or a strongly cappedor plugged aperture in a rock or other strong mineral formation.

The present application is a continuation-inpart of my earlierapplications, Serial No. 492,989, filed July 1, 1943, and Serial No.555,767, filed Ejeptember 25, 1944.

The above examples and detailed description have been given for purposesof illustration only. and it is to be understood that variations andmodifications may be made therein without departing from the spirit andscope of the appended claims.

What is claimed is:

l. A granular explosive composition comprising magnesium dispersoidobtained by shockchilling magnesium vapor, said dispersoid beingprotectively coated with hydrocarbon containing from 5% to 45% asphaltto reduce its activity in air, and a solid oxidizing agent in theproportion of from about 65% to about by weight oxidizing agent and fromabout 35% to about 15% by weight of said modified magnesium dispersoid.

2. A granular explosive composition compris ing magnesium dispersoidcontaining material obtained by shock-chilling the vaporous productsissuing from a reaction zone wherein magnesium oxide is reduced by acarbonaceous reducing agent, said dispersoid containing from 30% to 65%magnesium dust and having a protective V 11 coating of. hydrocarboncontaining from to 45% asphalt, and a solid oxidizing agent in theproportion of from about 65% to about 85% by weightof oxidizing agent"per from about 35% to about by Weight of said modified material.

3.1 311 explosive composition as in claim 2 wherein the oxidizing agentis a nitrate.

3 4. An. explosive composition as in claim 2 'Wherein the oxidizingagent includes sodium nitrate. v 5. An explosive composition as in claim2 wherein the oxidizing agent includes a perchlorate.

, 6. A granular explosive. composition bmnpris.

ing magnesium. dispersoid containing material obtained by.shock-chilling the vaporous products issuing from a reactionzonewhereinmagnesium is reduced by a carbonaceousreducing agent, said materialcontaining from to 65% magnesium dust and having .a protective coatingof hydro carbon containing from 5% to 45% asphalt, and

a solid oxidizing agent in the proportion of about 75% .by Weight ofsaid oxidizing agent per about 25% by Weight of said modifiedmate'rial.

7. A granular explosive composition comprising magnesiumdispersoid-containing material obtained by shock-chilling the vaporousproducts issuing from a reaction zone wherein magnesium oxide is reducedby .a carbonaceous reducingagent, said material containing from to 65%magnesium dust and having a protective coating of hydrocarbon containingfrom 5% to 45% asphalt, and a solid oxidizing agent in the proportion offrom about. 65% to about 85% by weight of oxidizing agent per from about35% to per 1.65 parts by weight of' Mg dispersoid-containing materialobtained-by shock-chilling the vaporous products issuing from a reactionzone wherein MgO is reduced by a carbonaceous reducing agent, saidmaterial containing from 30% to 65% m gnesi uust ;a.I1d.-bir1g'protectively coated by ahydrocarbon]containing from 5% to a a t.

1 1. A granularv explosive composition compris ing magnesium dispersoidcontaining material obtained by shock-chilling thevaporousproductsisuing from a reaction zonewherein magnesium oxide is reduced by 'acarbonaceous reducing agent, said material containing about 47%[05'magnesium dust and having a protective coating of liquid. hydrocarbon"containing, about;40% of asphalt, and a" solid oxidi ng agent infltheproportion of ,about.75% by weight. per about 25% by Weight .ofsaidlmodi fied materialj 12. A granular explosive composition comprismgmagnesium dispersoid-containing material obtained by shock-chilling thevaporous products issuing from a reaction zone wherein magnesium oxideis reduced by. a carbonaceous reducing agent, said material containingabout 50% of 'magnesium dust and having a protective coating of liquidhydrocarbon containing about of asphalt, and a solid oxidizing agent inthe proportion of, about 75% .by weight per about 25% by weight of saidmodified material. V

13. A granular explosive composition compris-, ing magnesiumdispersoid-containing material obtained by shock-chilling the vaporousproducts issuing from a reaction zone wherein magnesium about 15% byweight .of saidmodified material, 7

said solid oxidizing agent containing. a small amount, less than about1% of .moisture.

8. A granular explosive composition comprise ing about 25% by Weight ofmagnesium dispersoid-containing materialobtained by shockchilling thevaporous products issuing from .a reaction zone wherein-magnesium oxide,is reduced by a'carbonaceous reducing agent, said carbon containing.from 5% to 45% asphalt.

10. A granular explosive compositioncomprising NaNOs in the proportionof 4 parts by weight and KNO3 in the proportion of 1 partrby weightoxide is reduced by a carbonaceous reducing agent, said materialcontaining about 50% of magnesium dust and having a protective coatingof liquid hydrocarbon containing about 10% of asphalt and 90% ofdistillate, and a solid oxidizing agent in the proportion of about toabout by Weight of said oxidizing agent per from about 35% to about 15%by weight of said modified material.

' WILLIAM F. VAN LOENEN.

REFERENCES CITED The-following references are of record in the fileofthis patent:

UNITED STATES PATENTS Number Name Date 1,243,231 Smith Oct. 16, 19171,884,993 Hansgirg Oct. 25, 1932 2,101,904 Hansgirg Dec. 14, 1937FOREIGN PATENTS Number Country Date 22,030 Great Britain 1910 126,740Great Britain May 22, 1919 492,888 Great Britain Sept. 28, 1928 559,348Great Britain -1 Feb. 15, 1944

